Bamboo hair is a hair shaft abnormality that causes the hair strands to look similar to the knots in a bamboo stalk. Normal, healthy hair strands appear smooth under a microscope. Bamboo hair appears to contain nodules (bumps) or evenly spaced ridges. Bamboo hair is also known as trichorrhexis invaginata.

Bamboo hair is a feature of a disease called Netherton syndrome. Most cases of bamboo hair are caused by Netherton syndrome. It’s an inherited condition that results in red, flaky skin all over the body and allergy problems.

Bamboo hair can affect hair on top of the head, the eyebrows, and the eyelashes.

An inherited mutated gene called SPINK5 causes bamboo hair. A mutation in this gene leads to an abnormal growth process.

Bamboo hair is characterized by a weakness in the cortex (center) of your hair strands. Weak spots form at certain points along the strand. Nearby harder segments of the cortex press into these weak areas, causing nodules or ridges to form. This creates a bumpy appearance on your hair strand. It usually results in hair that breaks easily.

To diagnose bamboo hair, your doctor will pluck a hair from your scalp to observe it under a microscope.

To diagnose Netherton syndrome, your doctor may order a series of DNA tests or a skin biopsy to test for gene mutations. For a skin biopsy, your doctor will remove a small amount of skin tissue for testing in a lab. DNA tests are often used to test the SPINK5 gene for abnormalities.

Since the condition is a direct result of a gene mutation, there’s no current, known way to prevent the condition. But there are many types of lotions and ointments you can use to treat bamboo hair. These include:

emollients and keratolytics (especially those with urea, lactic acid, and salicylic acid) to moisturize your skin

You can minimize hair breakage by ensuring that your hair remains hydrated. Drink water regularly and avoid the use of alcohol-based hair products. They can cause your hair to dry out, which can worsen the breakage. There are also hair care products aimed at hydrating dry hair.

Avoid the use of chemicals in your hair, such as hair relaxers or perms. Don’t use them on damaged hair, either. Using these products may result in severe hair loss and cicatricial alopecia (scarring alopecia). This form of hair loss scars your hair follicles and makes future hair growth less likely.